1. Field of the Invention
The present invention relates to a process for the quaternization of triethanolamine fatty acid esters and imidazolinamides in a reaction medium containing alkoxylated fats or oils and to the use of the resulting reaction mixtures as the active ingredients in laundry softener compositions.
2. Discussion of the Background
Quaternized fatty acid esters of triethanolamine (N-alkyl-N,N,N-trihydroxyethylammonium fatty acid ester salts, called ester-quat below) or quaternized imidazolinamides (1-alkyl-2-alkyl-3-alkylamidoimidazolinium salts, called imidazolinium-quat below) have previously been used as the active ingredients in laundry softener compositions. More detailed descriptions both of the preparation and of the use of ester- and imidazolinium-quats (called generally quats below) as laundry softener active ingredients can be found in EP 0 295 385, DE 37 10 064, WO 91/17974, US 3 915 867, BE 888 678, DD 159 263 and EP 0 431 652.
The quaternizing agents conventionally used are, for example, benzyl halides, methyl halides, dimethyl sulphate or dipropyl sulphate. The quaternization reaction is conventionally carried out in a low molecular weight alcohol, such as 2-propanol, as solvent. The 2-propanol is not removed after quaternization, so that the quats are marketed as 85-90% strength compositions. The 2-propanol is used to ensure a flowable consistency, both of the reaction mixtures and of the quats formed, at the quaternization temperature (40-95.degree. C.). This is of importance for technical production reasons. Furthermore, the flowable consistency thus obtained assists in successful conversion of the quats to laundry softener formulations. The 2-propanol employed functions exclusively as a diluent and has no additional softening influence by interaction with the quats. However, the use of 2-propanol presents problems, due to its low flash point (12.degree. C.).
DE-A 42 15 689 describes the use of alkoxylated fats as the sole active ingredient in laundry softener compositions or in mixtures with the conventional nitrogen-containing cationic active softening ingredients, such as N,N-distearyl-N,N-dimethylammonium salts, quaternized or protonated imidazoline derivatives, quaternized fatty acid esters of triethanolamine and 2,3-dihydroxypropyl-trimethylammonium salt derivatives. These quaternized compounds are provided by quaternization according to conventional procedures in 2-propanol as solvent, and subsequent combining of the quaternized compounds with the alkoxylated fats. When mixtures of these alkoxylated fats with nitrogen-containing cationic active ingredients, such as ester-quats and imidazolinium-quats, are used, the mixtures are employed as 90% concentrates in 2-propanol.